xacro hello

basic xacro tags

#xacro  

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Table of Content

Install

sudo apt install ros-<version>-xacro

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usage

xacro hello.xacro > hello.xml

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include

include other xacro file

<xacro:include filename="other_file.xacro" />
<xacro:include filename="$(cwd)/other_file.xacro" />

args

• decalre arg
• arg usage

demo

Note

passing argument from cli :=

demo result

# run without argument
xacro hello.xacro > hello.xml

# run with argument
xacro hello.xacro > hello.xml var:=10

<?xml version="1.0" ?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from /home/user/projects/blog/examples/gazebo/xacro/hello.xacro | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
<!-- =================================================================================== -->
<robot name="">
  <data>10</data>
</robot>

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property

property

<?xml version="1.0"?>
<robot name="prop" xmlns:xacro="http://www.ros.org/wiki/xacro">
    <xacro:property name="prop1" value="0.1" />

    <data>${prop1}</data>
</robot>

output

<?xml version="1.0" ?>
<robot name="prop">
  <data>0.1</data>
</robot>

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condition

macro

<?xml version="1.0"?>
<robot name="condition" xmlns:xacro="http://www.ros.org/wiki/xacro">
    <xacro:property name="check" value="2" />
    <xacro:if value="${check == 1}">
        code for create A 
    </xacro:if>
    <!-- run if condition not true -->
    <xacro:unless value="${check == 1}">
        code for create B 
    </xacro:unless>
</robot>

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macros

macro

<?xml version="1.0"?>
<robot name="macro" xmlns:xacro="http://www.ros.org/wiki/xacro">
    <xacro:macro name="default_origin" params="x y z">
        <origin xyz="${x} ${y} ${z}" rpy="0 0 0"/>
    </xacro:macro>
    <xacro:default_origin x="1" y="2" z="3"/>
</robot>

output

<?xml version="1.0" ?>
<robot name="macro">
  <origin rpy="0 0 0" xyz="1 2 3"/>
</robot>

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loops

loops

<?xml version="1.0"?>
<robot name="loop" xmlns:xacro="http://www.ros.org/wiki/xacro">
        <xacro:property name="items" value="${[1,2,3,4,5]}" />

        <xacro:macro name="loop" params="items:=^">
                <xacro:if value="${items}">
                        <!-- pop first item from list -->
                        <xacro:property name="item" value="${items.pop(0)}"/>

                        <item>${item}</item>

                        <!-- recursively call myself -->
                        <xacro:loop/>
                </xacro:if>
        </xacro:macro>
        <xacro:loop items="${items}" />
</robot>

output

<?xml version="1.0" ?>
<robot name="loop">
  <item>1</item>
  <item>2</item>
  <item>3</item>
  <item>4</item>
  <item>5</item>
</robot>